Unfortunatly no codes at all. I've had the p0171 lean codes both banks but that's just telling me the fuel trims are lean due to vac leak or bad maf. Thanks for your help matey, I think I'm going to have to just buy a new MAF and see if it sorts things.

Setting aside the LPG, I picked up the wife from work on petrol. She kept an eye on the live data while I was driving. The short terms were at 25 on idle but if I put my foot down they dropped to zero while under heavy acceleration but as soon as i let off they went back to 25. Long terms apx 12-15 and even up to 20. Still wont go over 3k revs, just stumbles and burbles if that makes sense.